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Math Help - evaluating a parabola in equation form.

  1. #1
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    evaluating a parabola in equation form.

    I don't really understand how to do this question:

    If parabola y-2=a(x-3)^2 goes through the point (2,0), what is the value of a?

    I have been able to determine that its vertex is (3,2) meaning that 'a' must be negative.
    However, I have no idea about how to derive a number....

    Thank you for your help!
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  2. #2
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    e^(i*pi)'s Avatar
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    Can't you simply sub in (2,0) for (x,y)?

    0-2 = a(2-3)^2
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  3. #3
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    So I was overthinking it?
    I see, so 'a' is -2?
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  4. #4
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    e^(i*pi)'s Avatar
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    Yes, and it fits in with your working that it must be negative.

    You were told that the equation passes through that point so that point must be a solution for the equations. I thought it would be more complicated at first
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  5. #5
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    Quote Originally Posted by e^(i*pi) View Post
    Yes, and it fits in with your working that it must be negative.

    You were told that the equation passes through that point so that point must be a solution for the equations. I thought it would be more complicated at first
    Ah, I feel quite dim....
    But I have learnt something, so its not so bad!

    Thank you very much for your help!
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